One idea for my hierarchy project revolved around volume, or the idea of mass. Something like sea anemones that expand to eat and contract to protect themselves from predators. Of course I can not collect and tattoo a small colony of sea anemones. An alternative approach would be to fill up balloons with different volumes of air, or perhaps water for a more tactile-squishy feel. But how to get my words on there? Maybe I will come back to that.
On to plan B. Exploring different levels of tension. The idea is that the user opens these sliders to reveal a word, the amount of tension varies for each word according to how frequently it appears. More tension does not mean more hierarchy, it is actually the opposite because of the extra effort you require to pull on the slider to view the word you actually spend less time with the word therefore it will have less of a chance to make a visual impression on the viewer.
Click on the GIF file below to see the first attempts at the proto-type for a light tension sample.